Tribological Properties Of Serpentine Micro-nanoparticles And Mechanism Of Tribofilm Formation

Serpentine itself used as anti-friction and anti-wear materials is a hot topic in current research.A number of experimental data about its tribological properties from different lubricatingmedium has been obtained. There are some hypotheses about the mechanism of serpentineused as anti-friction and anti-wear additive, but the current studies are still lack of adequateexperimental basis and evidence. So, in order to provide the experimental and theoreticalbasis for the industrial application of serpentine as anti-friction and anti-wear materials, thispaper systematically carried out the friction experiments of serpentine in different lubricatingmedium, studied the composition, structure of the friction pair surface by a variety ofadvanced characterization methods, analyzed the interaction process of serpentine withfriction pair and the mechanism of film formation.In this paper, based on the previous research results, we did more study. Firstly, thetribological performance of micro-nano serpentine, surface modified serpentine, serpentine/Lacompounds as additive for base oil was investigated by a Plint high frequency friction tester atdifferent conditions. It is proved that serpentine has good tribological properties. Secondly,through different surface analysis method, we study and analyze the film formation processand the chemical and physical properties of the friction pair surface.The micro-structure of tribofilm was characterized by scanning electron microscopy, andthe results showed that, the addition of serpentine results in the formation of a non-uniformtribofilms on the friction pair surface. The serpentine particles exist in and between thetribofilms.The element distribution of the tribofilms was detected by energy dispersive X-rayspectroscopy, and the results showed that, in the system of serpentine/ZDDP/base oil, theelements in the tribofilm are P, S, O, Zn, Mg and Si. In the system of serpentine/fullformulated lubricating oil, the tribofilm consists of P, S, O, Zn, Ca, Mg and Si. Differentsystems have different elements distribution in different area of the tribofilm.The micro morphology of tribofilm was characterized by atomic force microscopy, andthe results showed that, the addition of serpentine reduced the roughness of the tribofilm. The cross section of the wear surface was got by focus ion beam, and it indicated that thethickness of the tribofilms is from about several dozen nanometers to about400nm.The XANES results showed that, the tribofilm formed by oil containing serpentinecontains serpentine, forsterite, SiO2and enstatite.